function [ ] = mx_eyelink_send_message_ex( )
%MX_EYELINK_SEND_MESSAGE_EX Send a data file message string to connected tracker
% with time offset.
%
% Parameters:
% exectime 	time offset. If the offset is 0, this function is the same as eyelink_send_message()
% msg 	Message to be sent
% Returns:
% OK_RESULT or LINK_TERMINATED_RESULT.
%
%
% OK_RESULT 0;
% LINK_TERMINATED_RESULT -100;
%----------------------------------------------------------------------------
% Copyright Eduardo Aponte 2013
% aponteeduardo@gmail.com